REACTION CASCADE IN THE SUPRAMOLECULAR PHOSPHORYLATION OF A BIS(GUANIDINIUM) DIOL

The reaction of the bis(guanidinium) diol 4 and the cyclic phosphodies ter 2 has been studied by P-31 NMR spectroscopy. A series of fast tran sphosphorylation steps was observed, each with a first order rate cons tant surpassing that of a control reaction by four to five orders of m agnitude. These accelerations are caused by electrophilic substrate ac tivation due to the guanidinium ions and by neighboring group effects: The substrate is held in close proximity to the hydroxy groups by ion pair formation. After phosphorylation of the 1,2-diol substructure, a rapid cyclization occurs leading to the final product 8. (C) 1997 Els evier Science Ltd.